Improvement in expanding taps



'EEANKMUEGATROYiL- IMPROVEMENT IN EXPANDING TAPS.

OE cLEvELAND, OHIO.

Specification forming part of Letters Patent No. 107,946, dated October4, 1870.

T0 a/ZZ whom itV may concern:

Be it known that I, FRANK MURGATROYD, of Cleveland, in the County ofCuyahoga and State of Ohio, have invented a certain new and usefulExpanding Tap and Drill, o f which the following is a specification.

The nature of this invention relates to an expanding tap and drill to beused in drilling and tapping pipe couplings and elbows; and it consistsof a drill having thread-cutters arranged in the sides in such a mannerthat they may be expanded tocut the thread and then Vcollapsed to enablethe drill to be withdrawn the mandrel is fitted a sleeve or ring, D,through which and the mandrel and the pin C is a slot, into which isfitted a key, d, the slot in the mandrel being longer thanthe others toallow the key to play back and forth a short distance, the purpose ofwhich is hereinafter shown. Uponthe drill B is tted a similar ring, D',with a key, d'. The outer end of the Fig. Ll is a perspective view ofthe drillA pin C is reduced in size by having two tapering shoulders, ee, turned upon it. Through the end of the drill are made mortises f, in

which are tted thread-cutters g g, the inside edges of which arev fittedto the pin C, the Vaction of the pin being to force the cutters outward.The ring D reachespart way over them, and prevents them dropping out.

The operation is as follows: The mandrel and drill are made to traverseback and forth by means of a cam or other suitable means. When thecutters are to be expanded the ring D comes Vin Contact with a plate forthe purpo'se,-when the center-pin will be carried forward and thecutters g g forced outward and perform "their work; when, by the motionof the mandrel forward, the ring D will come in contact with the work,causing the pin to be pushed back again, when the cutters will beimmediately collapsed, and the work may be freed from the drill. Thusthe mandrel. by itstraverse motion enables the work to be performed veryexpeditiously.

.I claim as my invention- The rings D and D', keys el and d', the pin C,and the cutters g g, in combination with the mandrel A and drill B,substantially as and for the purpose set forth.

F. MURGATROYD.

Witnesses: C. E. Trisitrfrs, GEO. HEsrEE.

